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Low-dose aspirin can improve accuracy of colorectal cancer test

Taking a low-dose aspirin prior to having a fecal occult blood test appears to increase the ability of the test to detect colorectal cancer, according to a new study.

The fecal occult blood test, which looks for blood in the stool, is a common test used to detect colon cancer because advanced colorectal tumors often bleed. Moreover, use of low-dose aspirin is a common practice in people ages 55 and older because studies show the therapy can reduce the risk of cardiovascular disease and cancer.

The study, from German researchers, examined 1,979 patients for the accuracy of fecal occult blood testing. Researchers found the test's sensitivity -- the correct identification of positive results -- was 70.8% for low-dose aspirin users compared with 35.9% for nonusers. Test specificity -- the correct identification of negative results -- was slightly lower among users of low-dose aspirin.

It appears that low-dose aspirin use increases the likelihood of bleeding from a colorectal tumor, thus increasing the odds that the test will detect blood.

"Our findings raise the hypothesis that test performance may be enhanced by temporary use of low-dose aspirin," the authors said. The study was published Tuesday in the Journal of the American Medical Assn.